Small, dark, and heavy: But is it a black hole?
arXiv:0902.0346
Abstract
Astronomers have certainly observed things that are small, dark, and heavy. But are these objects really black holes in the sense of general relativity? The consensus opinion is simply "yes", and there is very little "wriggle room". We discuss one of the specific alternatives.
arXiv comment17 pages, 8 figures. Technical seminar at the workshop "Black Holes in General Relativity and String Theory", 24-30 August, 2008, Veli Losinj, Croatia; V2: one reference added